Process for the manufacture of triarylcarbinol lactones

ABSTRACT

1. A PROCESS FOR THE MANUFACTURE OF TRIARYLCARBINOL LACTONE HAVING THE FORMULA:   R-N(-R1)-(1,4-PHENYLENE(A))-C&lt;(-O-CO-(5-Z-1,2-PHENYLENE)-)   -(1,4-PHENYLENE(B)-N(-R2)-R3   WHEREIN R, R1, R2 AND R3 EACH INDEPENDENTLY REPRRESRESENTS METHYL OR ETHYL, Z REPRESENTS HYDROGEN, DIMETHYLAMINO OR DIETHYLAMINO AND RINGS A AND B MAY OPTIONALLY BE SUBSTITUTED BY HALOGEN OR LOWER ALKYL, SAID PROCESS COMPRISING THE STEP OF OXIDISING A LEUCO COMPOUND HAVING THE FORMULA:   R-N(-R1)-(1,4-PHENYLENE(A))-CH(-(2-(HOOC-)-1,4-PHENYLENE)-   Z)-(1,4-PHENYLENE(B))-N(-R2)-R3   WITH AN INORGANIC PERSULPHATE SELECTED FROM THE GROUP CONSISTING OF AMMONIA PERSULPHATE, SODIUM PERSULPHATE, POTASSIUM PERSULPHATE AND METHYLAMMONIUM PERSULPHATE.

United States Patent 3,845,077 PROCESS FOR THE MANUFACTURE OF TRIARYLCARBINOL LACTONES Nigel Hughes, Manchester, England, assignor to Imperial Chemical Industries Limited, London, England No Drawing. Filed July 29, 1971, Ser. No. 167,440

Claims priority, application Great Britain, July 23, 1971,

41,606/71 Int. Cl. C07d /38 US. Cl. 260-3434 4 Claims ABSTRACT OF THE DISCLOSURE A process for the manufacture of a triarycarbinol having the general formula:

wherein 'R and R each independently represents an optionally substituted alkyl radical, R and R each independently represents an optionally substituted alkyl or aryl radical, X represents an optionally substituted aryl radical and rings A and B may be further substituted, or a lactone of said tniarylcarbinol, which process comprises oxidising the corresponding leuco compound with an organic or inorganic per-sulphate.

This invention relates to a chemical process and more particularly to a process for the manufacture of triarylcarbinols.

According to the invention there is provided a process for the manufacture of a triarylcarbinol having the general formula:

wherein R and R each independently represents an optionally substituted alkyl radical, R and R each independently represents an optionally substituted alkyl or aryl radical, X represents an optionally substituted aryl radical and rings A and B may be further substituted, or a lactone of said triarylcarbinol, which process comprises oxidising the corresponding leuco compound with an organic or inorganic persulphate.

The substituents R, R R and R are most preferably methyl or ethyl radicals. Other substituents which may be present in rings A and B include alkyl, alkoxy and halogen but it is preferred that said rings are unsubstituted.

Other substituents which may be present on the aryl radical represented by X include groups of the formula: NR R wherein .R is optionally substituted alkyl or aryl and R is hydrogen or option-ally substituted alkyl. Preferably X is a 4-dimethylaminophenyl radical which may carry further substituents.

It will be understood by those skilled in the art that the corresponding leuco compound referred to above is a compound of the formula:

wherein R, R R R and rings A and B have the significances stated above, and Y is an optionally substituted aryl radical.

3,845,077 Patented Oct. 29, 1974 and may be prepared by the oxidation of 2[4,4-bis(di methyl-amino)benzhydryl] -5-din'1ethylaminobenz0ic acid.

Persulphates which may be used in the process of the invention include ammonium persulphate, sodium persulphate, potassium persulphate and methylammonium persulphate.

Suitable amounts of persulphate to use are usually in the range of from 1.0 to 1.5 molar equivalents based on the leuco compound. The reaction may conveniently be carried out at temperatures between 20 C. and C. The process of the invention provides excellent yields of product and in the case of alkali-soluble leuco compounds, for example Leuco Crystal Violet Lactone, higher yields of purer products are obtained than when using previously described processes which use other oxidising agents.

The invention is illustrated but not limited by the following Examples in which all parts are by weight:

EXAMPLE 1 20.85 Parts of 2[4,4-bis(dimethylamino)benzhydryl1- S-dimethylaminobenzoic acid are dissolved in a solution of sodium hydroxide (6 parts) in water (250 parts). The solution is heated to 65 C. and a solution of potassium persulphate (15 parts) in Water (100 parts) is added over 15 minutes with stirring. After stirring a further 15 minutes the precipitated product is collected by filtration, washed with water and dried in air at 50 C.

18.75 parts of 3,3-bis(4-dimethylaminophenyl)-6-dimethylaminophthalide are thus obtained.

In place of 15 parts of potassium persulphate there may be used 12.5 parts of sodium persulphate or 12.0 parts of ammonium persulphate.

EXAMPLE 2 19.9 parts of 2[4,4'-bis(dimethylamino)benzhydryl] benzoic acid are dissolved in a solution of sodium hydroxide (6 parts) in water (250 parts). The solution is heated to 85:2 C. and a solution of potassium persulphate (16.5 parts) in water parts) is added over 1 hour with stirring. After stirring a further 2 hours at 85 C. the precipitated product is collected by filtration, washed with water and dried in air at 50 C.

After recrystallisation from n-Propanol 14.3 parts of 3,3-bis(4-dimethylaminophenyl)-phthalide are obtained.

Similarly the leuca compounds of column A of the following table may be oxidised to the phthalides given in column C by the persulphate(s) given in column B. The yield of pure product is given in column D.

Example A B C D 3 2-[4,4-bis(diethylamino) benzhydryl]-5-diethylamino- Ammonium 3,3-bis(4-diethylamin0pheny1)-6-diethylarnino 20.4 parts.

benzoic acid. persulphate. phthalide.

4 2-[4,4-bis(dimethylarnino)-2,2-dichlorobenzhydryH-S- .do 3,3-b1s[2-chlor0-4-(dimethylamino)-phcnyl]-6- 12.6 parts.

dimethylarninobenzoic acid. dimethylaminophthalide.

5 2-[4,4-bis(dimethylamino)-2,2-dimethylbenzhydryl]-5- Potassium 3,3-bis[2-methyl-4-(dimethylamino)-phenyl]-6- 13.35

' dimethylaminobenzoic acid. persulphate. dimethylaminophthalide. parts.

Iclaim: with an inorganic persulphate selected from the group 1. A process for the manufacture of a triarylcarbinol lactone having the formula:

wherein R, R R and R each independently represents methyl or ethyl, Z represents hydrogen, dimethylamino or diethylamino and rings A and B may optionally be substituted by halogen or lower alkyl, said process compris ing the step of oxidising a leuco compound having the COOH consisting of ammonia persulphate, sodium persulphate, potassium persulphate and methylammonium persulphate.

2. A process as claimed in claim 1 wherein the leuco compound has the formula:

COOH

UNITED STATES PATENTS 4/1956 Crounse 260343.4

OTHER REFERENCES Chemical Abstracts, vol. 41, 1947, 4027b relied on. Chemical Abstracts, vol. 49, 1955, 4952b relied on.

DONALD G. DAUS, Primary Examiner A. M. T. TIGHE, Assistant Examiner 

1. A PROCESS FOR THE MANUFACTURE OF TRIARYLCARBINOL LACTONE HAVING THE FORMULA: 